Self-sealing box blank



April 27, 1937. A, M Gm 'G 2,078,446

SELF SEALING BOX BLANK Filed July 21, 1932 I71 venior M. 777. 6' 2 1553 by 7 61702 77636 Patented 27, 1937 SELF- SEALING BOX BLANK Arthur M. Grigg, East Bralntree, Mass" assignor of one-hall to Ernest W. Parker, Dorchester, Mass, and one-sixth to Albert A. Oruickshank,

Milton, Mall.

Application July 21, 1932, Serial No. 623,722

4 Claims. (01. zzs-sa') application ofthis discovery to blanks and the This invention relates to self-sealing wrapping material and containers of the general nature disclosed in my copendlng application Serial No. 550,277, filed July 11, 1931, and of which this ap- 5 plication is a continuation in part. In its more specific aspect the invention relates particularly to wrapping material in the form of blanks adapted to be shipped to the consumer in flat form and thereafter folded into box or container form as required for use. The primary object of the invention is to produce a self-sealing blank having a portion of the surfaces thereof so treated as to be normally non-adherent to non-treated and unlike surfaces but adapted to cohere tenaciously when pressed into contact with each other and like surfaces and. to retain such cohering property for a substantial period of time while exposed to the air in storage.

It will be understood that boxes or containers and are, therefore, bulky, inconvenient to handle a in quantities and may be'shipped and stored only at relatively great difiiculty and expense. On the other hand, the setting up .of blanks heretofore known has been such a tedious task and has required the use of such additional equipment and material, as paste pots, adhesive strips, twine, etc., as substantially to negative the advantages gained by shipping and storing in blank form. An object of my invention is the production of a self- .sealing blank which can be shipped and stored flat and can be readily and conveniently set up for use as required without resort to any of the said additional equipment and material, thus retaining the shipping and storing advantages without loss in the setting up came blanks.

I have discovered that by coating suitable paper or the like with a solution of rubber latex and then allowing the coating todry there is produced a moisture-resisting surface which'is normally non-adherent to surfaces of other molecular composition but which has the property of cohering tenaciously to itself when two of such surfaces substantial period of time while exposedto the air in storage. The invention herein resides in the like which are to be folded into box or container form. The blanks, comprising one or more sheets of suitable material, such as cardboard, are prepared in a manner adapting them to be folded or otherwise brought together to form containers of the desired shape, size, etc. In preparing the same the surfacesv which are to come into contact in the completed and closed container are coated with latex solution in accordance with my invention whereby such surfaces, when brought together, will cohere tightly and thus securely maintain the parts or portions in the proper relation without the aid of any additional equipment or material. The product in sheet or blank form may also be handled conveniently under commercial conditions since the coated surfaces are non-adherent and, consequently, the blanksmay be stacked with dissimilar surfaces in contact or with interposed separating sheets between coated surfaces. In may furthermore be stated that while the product of the invention may be used for wrapping, packing and distributing any product adapted thereto, it is especially useful in packing food or other products wherein it is desired to prevent the entrance or exit of moisture to or from the package during the time elapsing between the packing and distribution of the product or while the product is held in storage, the

Percent Water 58 Rubber 34 Resin 2 Protein 2 Mineral 4 Preservative A trace It will, of course, be understood that the coating may be applied in any convenient and suitable manner, such as by atomized spray, the silk screen process, knife edge scraping process, brush, calender rolls, etc., or any combination thereof.

The. coating thus formed is extremely thin, being I not more than enough to cover the surface uniformly and continuously. The coated surfaceis then dried, or allowed to dry, whereupon it becomes non-adherent. It cannot be termed tacky although it exhibits a slight tendency to cling to the hand. As already explained, the coated and dried sheet may be handled conveniently so long as its coated surfaces are not brought into contact. when folded upon itself,,however. sothat two coated surfaces are brought together, the coated surfaces of the sheet, 'upon contact and especially upon being subjected to pressure, instantly form a secure seal and this seal is effected without any other preliminary treatment, such as the wetting of the coated surface with a solvent.

It will thus be apparent that my invention con-.

It will be understood that the latex solution of the formula stated above is by way of example only and that its composition may be widely varied to meet different conditions of use, the primary purpose of the latex or latex-like solution being to provide a surface coating which will not adhere to other surfaces but which is adapted to cohere tenaciously to a like surface and to retain such cohering property for a substantial period of time while the blanks are in storage and exposed to the air. It is to be understood that any latex solution or its equivalent which has these characteristics comes within the scope of my invention.

These and other features of the invention will be best understood and appreciated from the following description of certain embodiments thereof, selected for purposes of illustration and shown in the accompanying drawing, in which Fig. 1 is a perspective view of a box constructed in accordance with my invention; and

Fig. 2 is a bottom view of the treated blank from which the box is formed.

Proceedingnow with a description of the invention, as illustrated in the accompanying drawing, l0 indicates in bottom plan view a one-piece blank treated in accordance with my invention whereby the box I! may be formed therefrom without the aid of any additional equipment or material. Theblank, comprising a bottom section l4, side sections IS, a cover section It and: flaps attached to the sections, is scored along the dotted lines between these .sections and between the sections and flaps attached thereto, whereby it may be readily foldedlto the form shown in Fig. 1. The surfaces of the blank which are to come into contact and which it is desired to seal together when the blank is folded into box form are coated with latex solution in the manner already described. It will be understood that the blank as thus constructed and treated is complete and may be set up into box form at any future time merely by folding the blank, as will now be described.

Attention is first called to the fact that Fig. 2 shows the face of the blank which forms the exterior surfaces of the box. In folding the blank to box form, the end fiaps 20 of the sides l6 are first folded to a position relatively right-angular to the sides l6 and the sides ii are likewise folded relatively right angular to the bottom section H, the free edges of the end flaps thus coming into and to end relation, as shown in Fig. 1, and the coated surfaces of the flaps facing outwardly. The end walls 24 are then folded to contact their inner coated surfaces 25 with the coated surfaces of the flaps 20 and pressure is applied thereto whereby the coated surfaces are brought intoclose contact. These surfaces thereupon cohere tightly together and hold the ends of the box securely sealed in the folded relation of Fig. 1. The inner surfaces 26 of the cover flaps are likewise latex coated, as are also the top portions 28 of the end walls and front wall. folded in place over the box and these treated surfaces are brought into contact, the surfaces cohere tightly together and form a secure seal. It will thus be seen that the application of my invention to the sheet produces a blank from which a box may be formed and sealed merely by folding the blank, thusvnot only effecting a great saving of time, material and expense but also producing a stronger box and tighter seal more efllciently and more economically than has been possible in boxes heretofore known. It will be noted that the non-coated areas of the opposite faces of the blank I0 form the interior and exterior faces or walls of the box.

It will be understood that the'invention and improvement herein described is characterized in its broader aspect by the use of a water emulsion of rubber, exemplified by that which also occurs naturally as rubber latex, as the material from which is produced by deposit a thin film or precoating of sealing composition on the box blanks of my invention. Where rubber-is subjected to mechanical attrition and working in a mill, for the purpose of making smooth cements in organic volatile solvents, it is to some-extent, though not seriously, weakened by disruption or disintegration. But the action of organic volatile solvents, such as naphtha or benzol, is far more destructive of the rubber aggregates than the mechanical stages of preparation, in that the swelling action of these solvents, which are ini- I rubber.

Such is not the case with water-emulsions of rubber, wherein the integrity of dispersed rubber aggregates is preserved, and further, protected by the protective colloid films which surround these aggregates individually, while in emulsion or suspension. In the case of natural latex, these rubber aggregateshave not even been subjected to mechanical disruption. For these reasons, thin films or precoatings of sealing materials obtained by depositing rubber from water emulsion possess superior ageing capacity, 1. e. permanency of constitution, whereby such precoatings retain their cohering property for a substantial period of time while the precoated blanks are held in storage. It may also be stated that, rubber latex, being a water-emulsion of rubber, does away with any danger from fire risks which must be considered in the use of rubber cements. The expression rubber latex and similar expressions contained herein are intended to include wateremulsions of rubber derived from any source.

It is believed that my invention and its use will be clearly apparent from the above description, it being understood, however, that the application of the invention to the use herein illustrated and described is by way of example only. The blanks and containers formed in accordance with the invention are convenient to use, effect a saving in both labor and material, are superior to such products heretofore known and used for- Thus when the cover is tially absorbed into the rubber, disrupts the rubhas been heretofore described. The latex coating forms a self-sealing surface which will retain its sealing property for a substantial period of time during which the blanks are in storage and are being drawn upon for use, and such surfaces, when brought into contact, form a flexible seal which will retain its hold indefinitely and tenaciously and will not jar loose by shocks, whereas glue and like seals heretofore used dry out, frac- 10 ture upon shock and result in opening up, thus causing loss and destruction of the contained products. It will furthermore be clear that my invention entirely disposes of exterior holding means, such as twine, gummed tape, etc., which have heretofore been necessary in the packaging of various products.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent is:

i. A foldable self-sealing box blank of relatively stiff fibrous sheet material scored along straight lines about which the blank can be folded to provide difierent sections on opposite sides thereof, and thin film precoatings of rubher deposited on surface portions of said sections from a water emulsion of rubber in which the integrity of the rubber in the emulsion is preserved in the said rubber deposited therefrom on said portions, said portions on different sections being adapted to be brought into face to face surface contact with each other in the folding of the blank on said lines to form a box and said;

precoatings being normally non-adherent to noncoated and unlike surfaces but adapted to cohere tenaciously when pressed into contact with each nther and to retain such cohering 'property for a substantial period of time while exposed to the air in storage.

2. A self-sealing blank comprising a single 40 sheet of relatively stifi fibrous material scored on iines about which the blank canbe readily folded to form a box, thin film precoatings of a sealing material deposited on face surfaces of the blank which come into contact when the 5 blank is thus folded, said sealing material comprising as its basis rubber characterized by sub stantial conservation after drying of the integrity of rubber particles dispersed in water emulsion, and thin precoatings of said sealing material deposited on surfaces of the blank which form exterior surfaces of the folded box and adapted to receive and cooperate with like precoated surfaces on a cover for the box, saidprecoated surfaces being non-adherent to other surfaces but adapted to cohere tenaciouslyto each other when pressed into contact and to retain such cohering property for a substantial period of time while exposed to the air in storage.

3. A foldable blank of fibrous sheet material having a plurality of sections adapted to form the walls of a box and a plurality of flaps attached tor the sections, the surfaces of the sections and flaps which come into contact'when the blank is folded into box form being precoated' with a thin surface film of a sealing material whereby to provide a secure cohering seal holding the parts in folded relation, said sealing material comprising as its basis rub- ,ber deposited from a water emulsion thereof without disruption, during deposition, of the originally suspended rubber aggregates, and a cover section having a flap adapted to engage against a sidewall of the box, the contacting surfaces of the flap'and side wall being precoated with a thin surface film of said sealing material for the purpose described and the precoated Slll. faces being normally non-adherent to non-coated and unlike surfaces but adapted to cohere tenaciously when pressed into contact with each other and to retain such cohering property for a substantial period of time while exposed to the air in storage. 4. An article of manufacture comprising'a selfsealing blank of relatively stiff fibrous sheet material scored along relatively spaced lines to provide independent sections on opposite sides of the scorings and having portions of both faces thereof adjacent to the edge of the blank coated with a thin surface film of a sealing material" and dried to provide surfaces on the diflerent sections v normally non-adherent, to other and unlike surfaces but adapted to cohere tenaciously when pressed into contact with each other and to retain such cohering property for a substantiai period of time while exposed to the air in storage, the non-coated areas of said faces being adapted to form the interior and exterior faces of a box formed by folding the blank on the scored lines and pressing said coated portions of the opposed faces into contact, said sealing material comprising as its basis coagulated rubber characterized by substantial conservation after drying of the integrity of rubber particles disposed in latex emulsion.

ARTHUR M. GREGG. 

